The invention relates to a manual actuating device for the actuation of all appliance especially subjected to a force in a direction opposite to the actuation direction, especially in the production of mineral oil or natural gas, such as a blowout preventer (BOP), valve, actuator, throttle or similar, with a rotating spindle, which can be connected to a displacing element of the appliance, moveable in the actuation direction, and with a regulating device, drive-connected through at least one mechanism and which can be manually actuated.
Such a manual actuating device is, for example, known in connection with a manually actuated blowout preventer (BOP). Such a blowout preventer is used to close a borehole in the production of mineral oil and natural gas. Closure occurs here through, for example, bringing together two clamping jaws from opposite sides of the borehole. These clamping jaws engage tightly in one another and close off the riser.
The relevant clamping jaws are here the displacing elements of the BOP, which are subjected to a force through the pressure within the riser in the direction opposite to the actuation direction of the manual actuating device. The applied force arises through the high pressure within the riser which, for example, can be up to 700 bar or even higher. This means that the displacing element must be moved against a load of 20 tonnes or more.
With the manual actuating device known in practice the regulating device which can be manually actuated is normally a handwheel which moves a rotating spindle in its longitudinal direction via an intermediate mechanism and thereby also correspondingly moves the displacing element connected to the rotating spindle.
From practice hydraulically actuated actuating devices of the above type are also known. With these however appropriately complex equipment for the hydraulic supply, pressure generation, control of the hydraulic system, etc are needed.
With the above mentioned manual actuating device it has been established that the handwheels must be relatively large in order to move the displacing element and the rotating spindle despite the large load acting against the direction of actuation. For this purpose, mechanisms have been produced which exhibit a low efficiency and, although they reduce the forces required for actuating the regulating device, the number of revolutions for actuating the regulating device is substantially increased. This led to this type of solution being essentially too slow in an emergency for moving the displacing element or bringing the closing jaws of the BOP together.